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Onramp · 01-08-2018, 06:56

RWCable,

Analogue cordless phones used to operate around 27 - 35Mhz which was within the band of the return path. Often, houses had unterminated Coax connectors in their living rooms which would pick up stray signals. That was the new build system, however. The older system was simply a nest of wires, ultimately coming from a nearby hill, amplified in small grey pillars around the street. It had no return path and supported up to around 550MHz (hence the name Jerrold 550) - although such converters were in use on both the older and newer network.

The analogue cable boxes did support a return path, but it was only used on the new build star networks built in the 90s. There was a module which clips onto the back of the box over the coax connectors called a talkback unit which could be used for ordering pay per view events, etc. Not everyone had one of those, however.

I think the F button could be used to manually map channels from the allowed bouquet to specific channel numbers. I can't really remember seeing it used for anything other than displaying the serial number of the box, however. I think you have to press F and then key in 0, 2. I could be wrong though, this was a long time ago. It didn't do anything too fancy beyond that as far as I remember, but some boxes supported extra features, such as timers. The program selection was delivered to each box individually via a "hit" which would map channels and decide which ones could have their vertical blanking signal reintroduced in order to "unscramble" the picture.

There was something to do with a P/B indicator which had something to do with a "barker" channel - but I can't remember what that was intended for.

The whole system was General Instrument / Motorola and was operated by a central controller known as the ACC-4000. You can still find the manual for those online. I doubt anyone uses these systems any more and there's nothing really secretive about how it works. The whole setup is really basic.

EDIT: I might have been wrong about the P/B thing http://www.eddiesegoura.com/cablebox.htm

01-08-2018, 06:56	#7
Onramp Inactive Join Date: Sep 2016 Posts: 210	Re: Analogue Cable Memories RWCable, Analogue cordless phones used to operate around 27 - 35Mhz which was within the band of the return path. Often, houses had unterminated Coax connectors in their living rooms which would pick up stray signals. That was the new build system, however. The older system was simply a nest of wires, ultimately coming from a nearby hill, amplified in small grey pillars around the street. It had no return path and supported up to around 550MHz (hence the name Jerrold 550) - although such converters were in use on both the older and newer network. The analogue cable boxes did support a return path, but it was only used on the new build star networks built in the 90s. There was a module which clips onto the back of the box over the coax connectors called a talkback unit which could be used for ordering pay per view events, etc. Not everyone had one of those, however. I think the F button could be used to manually map channels from the allowed bouquet to specific channel numbers. I can't really remember seeing it used for anything other than displaying the serial number of the box, however. I think you have to press F and then key in 0, 2. I could be wrong though, this was a long time ago. It didn't do anything too fancy beyond that as far as I remember, but some boxes supported extra features, such as timers. The program selection was delivered to each box individually via a "hit" which would map channels and decide which ones could have their vertical blanking signal reintroduced in order to "unscramble" the picture. There was something to do with a P/B indicator which had something to do with a "barker" channel - but I can't remember what that was intended for. The whole system was General Instrument / Motorola and was operated by a central controller known as the ACC-4000. You can still find the manual for those online. I doubt anyone uses these systems any more and there's nothing really secretive about how it works. The whole setup is really basic. EDIT: I might have been wrong about the P/B thing http://www.eddiesegoura.com/cablebox.htm Last edited by Onramp; 01-08-2018 at 07:05.